Frequency-domain study of the mechanical response of living striated muscle

Summary Small-amplitude sinusoidal displacements, in the frequency rang 4–100 Hz, were applied to intact whole frog sartorius muscle whilst in a state of tetanus. At low frequencies the muscle, was observed to do oscillatory work, while at higher frequencies it tended towards elastic behaviour. Frequency-response plots obtained were compared with those from other muscle preparations. Results were interpreted in terms of mechano-chemical transduction properties of muscle.The authors wish to thank the Australian Research Grants Commission for provision of the laser, and L. I. Patterson for construction of the mechanical apparatus.     

Retroviral antigens on gs- chf- leukocytes

It has recently been suggested that the endogenous retroviruses present in many different species might be involved during stimulation of the immune system of their hosts. We have now studied the expression of two avian retroviral antigens p27 and gp85 in chicken lymphoid cells by indirect immunofluorescence (IIF) and by complement-dependent microcytotoxicity (CDM). We have now found that these viral antigens are expressed in peripheral blood leukocytes of adults and embryos and in splenic and bursal lymphocytes of Spafas gs- chf- chickens but they are not expressed in fibroblasts cultured from the feather follicles of the same individual adult birds nor in fibroblasts cultured from embryos of the same flock. The differential expression of viral antigens in leukocytes may be related to a specific property or function of these cells.     

Solubility of the neurosecretory products of Crepidula fornicata Phil., a prosobranch mullusk]

Study of solubility of neurosecretory products in Crepidula fornicata shows that the presence of ethanol in the fixative is incompatible with good fixation. This character permits the choice of a more effective extraction technique. An experimental study in organ culture shows that the action of differentiation of brain appears in the extract obtained by this method.     

Characterization of the domestic horse (Equus caballus) karyotype using G-and C-banding techniques

Summary Giemsa banding techniques have been used to identify the chromosomes of the domestic horse.     

Effect of biogenic amines on γ-amylase (acid α-glucosidase)

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Bacteriocinogeny inProteus rettgeri

Zusammenfassung In 2 von 7 Stämmen vonProteus rettgeri gelang die Induktion von Bakteriozinen unter der Einwirkung von Mitomycin C. Die gewonnenen Bakteriozine waren chloroformbeständig, trypsinresistent und hitzelabil.